title: Digital dermatitis in cattle is associated with an excessive innate immune response triggered by the keratinocytes.
abstract: BACKGROUND
  Digital Dermatitis (DD) is a common disease of dairy cows, the pathogenesis of which is still not clear. This study examined some host responses associated with the typical lesions, in an attempt to further elucidate the pathogenesis of the disease. Twenty four samples representing the 5 different clinical stages of DD (M0-M4) were collected from slaughtered cattle for histopathological and immunological analyses.
  
  
  RESULTS
  Significant increases in total epidermal thickness were found in M2, M3, and M4 when compared with M0 and M1. M3 samples, when compared with M0 and M1, were characterized by a significant increase in the thickness of the keratin layer. Counts of both eosinophils and neutrophils were at a maximum in the M2 stage and decreased in the M3 and M4 stage. A significant increase in IL8 expression was observed in the M2-M3 stages of the disease and immunohistochemical staining showed the source as keratinocytes, suggesting an important role for keratinocyte-derived IL8 in the pathogenesis of DD.
  
  
  CONCLUSIONS
  Results of the present study point to a strong stimulation of the innate immune response at the level of the keratinocytes throughout most of the clinical stages, and a delayed response of the adaptive immune reaction.
authors.affiliation: Department of Reproduction, Obstetrics, and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium. Geert.Opsomer@UGent.be.
authors.forename: Walid
authors.initials: W
authors.lastname: Refaai
authors.forename: Richard
authors.initials: R
authors.lastname: Ducatelle
authors.forename: Peter
authors.initials: P
authors.lastname: Geldhof
authors.forename: Belgacem
authors.initials: B
authors.lastname: Mihi
authors.forename: Mahasen
authors.initials: M
authors.lastname: El-shair
authors.forename: Geert
authors.initials: G
authors.lastname: Opsomer
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology* / Q000473:pathology; D003001:Cloning, Molecular; D018076:DNA, Complementary; D003872:Dermatitis / Q000276:immunology / Q000662:veterinary*; D004804:Eosinophils; D005260:Female; D005534:Foot Diseases / Q000276:immunology / Q000662:veterinary*; D005786:Gene Expression Regulation / Q000276:immunology; D007113:Immunity, Innate / Q000502:physiology*; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D015603:Keratinocytes / Q000502:physiology*; D008214:Lymphocytes; D009504:Neutrophils; D012313:RNA / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary
chemical_list: D018076:DNA, Complementary; D016209:Interleukin-8; D012313:RNA